<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Title</title>
	<link rel="stylesheet" href="./css/bootstrap.min.css" integrity="sha384-xOolHFLEh07PJGoPkLv1IbcEPTNtaed2xpHsD9ESMhqIYd0nLMwNLD69Npy4HI+N" crossorigin="anonymous">
	<script src="./js/jquery.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
	<script src="./js/bootstrap.bundle.min.js" integrity="sha384-7ymO4nGrkm372HoSbq1OY2DP4pEZnMiA+E0F3zPr+JQQtQ82gQ1HPY3QIVtztVua" crossorigin="anonymous"></script>
	<style>
		[class*=col-]{
			border:1px solid green;
			text-align: center;
			font-size: 50px;
		}
	</style>
</head>
<body>
	<div class="container">
		<div class="row">
			<div  class="col-6 col-sm-4 col-md-3 col-lg-2 col-xl-1">1</div>
			<div  class="col-6 col-sm-4 col-md-3 col-lg-2 col-xl-1">2</div>
			<div  class="col-6 col-sm-4 col-md-3 col-lg-2 col-xl-1">3</div>
			<div  class="col-6 col-sm-4 col-md-3 col-lg-2 col-xl-1">4</div>
			<div  class="col-6 col-sm-4 col-md-3 col-lg-2 col-xl-1">5</div>
			<div  class="col-6 col-sm-4 col-md-3 col-lg-2 col-xl-1">6</div>
			<div  class="col-6 col-sm-4 col-md-3 col-lg-2 col-xl-1">7</div>
			<div  class="col-6 col-sm-4 col-md-3 col-lg-2 col-xl-1">8</div>
			<div  class="col-6 col-sm-4 col-md-3 col-lg-2 col-xl-1">9</div>
			<div  class="col-6 col-sm-4 col-md-3 col-lg-2 col-xl-1">10</div>
			<div  class="col-6 col-sm-4 col-md-3 col-lg-2 col-xl-1">11</div>
			<div  class="col-6 col-sm-4 col-md-3 col-lg-2 col-xl-1">12</div>
		</div>
	</div>
</body>

</html>